1. Technical Field
The disclosure relates to a heat pump air-conditioning system and a method for controlling the same, and more particularly to a heat pump air-conditioning system and a method for controlling the same capable of changing the flow direction of a refrigerant to perform different heat exchange modes.
2. Related Art
Hot water, cool air and warm air have already become indispensable parts of people's daily life. For most people, hot water is provided by a heat pump device, and cool air and warm air are provided by an air-conditioner.
The heat pump device comprises a heating device and a water supply device. The water supply device provides water to the heating device, and the heating device heats the water to a particular temperature for use.
The air-conditioner at least comprises a compressor, an expansion valve, an evaporator, a condenser, a heat dissipation device and a fan. A refrigerant carries out heat exchange in the evaporator and the condenser, and provides cool air or warm air through the fan.
In view of the above, the air-conditioner and heat pump device are separate devices and are respectively limited in use or price. Therefore, some manufacturers have developed a composite heat pump air-conditioning system having the functions of both the air-conditioner and the heat pump. Specifically, the composite heat pump air-conditioning system has a three-way control valve and an electronic expansion valve, so as to operate as the heat pump or provide the cool air and the warm air by changing the flow direction of the refrigerant.
However, in the operation process of the composite heat pump air-conditioning system, when the vapor refrigerant passes through the electronic expansion valve, an excessive pressure drop or over-expansion may occurs, and therefore, the coefficient of performance (C.O.P) of the system is lowered.